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    <title>Document</title>
    <script>
        let a = 'window'
        
        function father() {
            let a = 'father';
            function fn() {
            console.log(a); //window
        }
            function children() {
                let a = 456
                console.log(a); //FATHER
                fn()
            }
            children()
        }
        father()
    </script>
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</body>

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